Debris collected at military test ranges varies in type, size, density, and level of contamination. Currently, this material is decontaminated to a 3X level by cleaning and visual inspection. In order to be classified to the 5X level for release to the public without restriction, metal debris must be thermally treated. As thermal decontamination ovens are primarily fixed installations, transportation costs for potentially contaminated material are prohibitive. This project demonstrated and validated a transportable flashing furnace (TFF) that can be easily deployed for high-volume, repeatable, certifiable 5X decontamination.
Heating explosive-contaminated material above 600 degrees Fahrenheit has been shown to remove all energetic material. El Dorado Engineering, Inc. developed a TFF to decontaminate material on-site via a 48-foot trailer that is transportable over highways. The TFF is 5-feet high, 7-feet wide, and 17-feet long. The bottom of the furnace rolls out for easy loading of large, heavy, or awkward batches. Assembly and disassembly of the TFF in the field is completed in approximately one day. The furnace cycle time is 45 to 90 minutes, depending on load size, and the ceramic wool insulation allows for rapid heating and cooling. The main controls for the TFF are on the trailer although there are pendant mounted controls for remote operation. Temperature recording enables verification of each load's temperature.
The three-phase demonstration focused on test range applications. Phase 1 demonstrated that the TFF could be used to flash range material to a 5X level. Explosive-treated coupons were used to verify that explosive material would be eliminated by the flashing cycle. These coupons were sent to a laboratory for analysis following decontamination and found to be completely clean from explosive residue. In addition, an effective basket design was established to structurally withstand the heat, contain any molten aluminum created during the flashing cycle, and allow efficient heating of the material. Phase 2 demonstrated that the heat cycle does not vary significantly based on the density of the materials flashed. Phase 3 established operating parameters that would maximize throughput. Labor, materials, and cycle times were determined. A reliable heat soak cycle time also was developed that assures metal decontamination and eliminates the costs and problems associated with instrumenting each load. Emissions levels were tested to verify that they are insignificant and will have little or no impact on siting the TFF. As expected, all emissions were below established limits. Overall, the demonstration confirmed that the TFF can be used to decontaminate test range metal debris to a 5X level efficiently, effectively, and economically.
The TFF can decontaminate 4,375 tons of scrap per year when operating at the maximum throughput. As range scrap is comprised largely of steel, the total overall cost of decontaminating loads of test range metal debris, including all variable costs and amortized capital costs, is $86 per ton. However, some scrap piles contain a significant amount of aluminum. Salvagers are currently buying scrap aluminum at a price 40 times greater than steel. If scrap loads are composed of 10% aluminum, total overall costs for decontaminating this material drop to $46.60 per ton. (Project Completed - 2006)